Alcohol, ester, ether or ketone derivatives having a spiro-type skeleton are a quite well known class of chemicals. However, and surprisingly, despite the large number of structures reported in the prior art, only a few compounds of formula (I), hereinbelow described, are known.
For instance, Novikova et al. in their Naftekhimiya, 1984, 24, 475 paper disclose, as chemical intermediates, a mixture of the ketones 2,8-dimethyl spiro[5,5]undec-8-en-1-one and 2,9-dimethyl spiro[5,5]undec-8-en-1-one, as well as a mixture of the tertiary alcohols 1,9-dimethyl spiro[5,5]undec-8-en-1-ol and 1,8-dimethyl spiro[5,5]undec-8-en-1-ol. The same authors in their Naftekhimiya, 1986, 26, 3 paper disclose, still as chemical intermediates, a mixture of the tertiary alcohols 1,7-dimethyl spiro[4,5]dec-7-en-1-ol and 1,8-dimethyl spiro[4,5]dec-7-en-1-ol.
Furthermore, Nakamura et al. in Chem.Commun, 2002, 1648 disclose, as chemical compounds, the two spiro-ketones 8,9-dimethyl spiro[5,5]undec-8-en-1-one and 7,8-dimethyl spiro[4,5]dec-7-en-1-one.
However, there is no mention or suggestion, in any of said documents mentioned hereinabove, of the specific organoleptic properties of the invention's compounds, or of any potential usefulness of said compounds as perfuming ingredients.
Amongst the compounds having a structure similar to that of the compounds of the present invention, only few are known in the prior art to have an odor which may be of interest for the perfumery industry. In U.S. Pat. No. 4,668,432 there are reported some alkyl substituted oxo-spiro[4,5]dec-7-ene derivatives which possess odors dominated by minty or animal top-notes. Similarly, U.S. Pat. No. 4,622,172 discloses 9-methyl-11-isopropyl-spiro[5,5]undec-8-ene which imparts to compositions a fresh minty and spicy aroma. All the compounds disclosed in U.S. Pat. Nos. 4,668,432 and 4,622,172 have a structure and an odor which differ from those of the compounds of the present invention.